Manufacture of shoes



Sept 5-, 1950 J. J. BROPHY 2,520,995

MANUFACTURE OF SHOES Filed Dec. 22, 1948 2 Sheets-Sheet 1 Sept. 5, 1950J. J. BROPHY 2,520,995

MANUFACTURE OF SHOES Filed Dec. 22, 1948 2 Sheets-Sheet 2 Patented Sept.5, 1950 E D S TAT ES PAT ENT ()"FF l C E MANUFACTURE OF SHOES John J.-Brophy, Salem, Mass., assignor to United Shoe Machinery Corporation,Fle'mington', N. J'., a; corporation of New Jersey Application-December22, 1948, Serial No. 66,607

Claims. I

Thisinvention relatesto the manufactureof shoes and particularly to animprovement in methods of making. shoes. However, in other aspects theinvention contemplates a novel apparatus for use in practicing thisimprovement in methods of makingshoes, as well as a novel product whichresults therefrom.

In the manufacture of shoes, it is of great importance-that every tack,temporarily employed to, hold-the insole .on the last, be withdrawn orremoved from the-insoleand last before an out- .sole .is applied,because thereafter a tack cannot be pulled out and the tack, leftextending into the inside of the shoe, may only be partiallyremo.ved,.after the lastis pulled, by the time-consuming job of s ippingthe point off fromthe insideof the shoe as close tothe insole aspossible. Suchashoe is likely. to render but short .service. to thewearer before the remainder of .the tackwill work higher into theshoeand eventually penetrate the sock lining.

Heretofore, it. hasbeen necessary to withdraw each ofthe. insolepositioning tacks individually, either by a hand toclor by atack pullingma- .chindand, in spite ofv all practical precautions off the tack,leaving the embedded point diffi- ,cult todetect and extract until afterthe last has been pulled.

Another objectionable feature of the present manner .of removing tacksis that permanent damage. may be occasioned to the insole by the tackpuller which, inorder to grasp and with- .draw a.d.eeply embedded tack,frequently has to .bite .deeply into the texture of the insole, thusproducinglarge gouged out areas which weaken the ultimate shoeconstruction and necessitate sebsequent doctoring with bottom filler in.order.,to insure. an even treading surface for the foot.

It is-an, object of this invention to provide an improvementin methodsof making shoes which will result in. theelimination of the difficulties.Whichhave just been mentioned. More specifically,- thisvimprovementcomprises temporarily securing an insole toa last-by means offasten- .ings. which, after the upper. has been attachedto .the insoleand, before the outsole is applied, may be easily and certainly removedwithout damaging the insole. For this purpose, and in accordancewitha-.-feat ure of the invention, the fastenings.for example tacks, ,aremadeof read- 2. ily fusible material so that they may be easily removedby melting atrelatively low temperatures which will have no adverseeffect on the insole itself. In the herein illustratedv embodiment ofthe invention, two different. types of fastening materials aresuggested, namely, low melting point metals and plastics, the former ofwhich may be melted by the action of inductionheating, while the lattermay be melted by means of dielectric heating.

Another object of the invention. is to provide anovel apparatus formelting andremoving. fastenings of the kinds setforth above from thebottom of a shoe. For this purpose, there is. provided a table forsupporting a shoe by engagement with itsbottom and having meansforheat,- ing insole fastenings to melt them and cause them to drop out oftheshoe bO-ttom. Preferably, means are also provided for imparting avibratory movement to the table for the purpose of dislodging the meltedfastenings and thus facilitatingtheir removal.

A still further object of the invention is to provide a novel productfor use in the manufacture of shoes. Thus, invention will also berecognized in the novel intermediate product comprising a last having aninsole secured thereto by means of readily fusible fastenings whichmaybe easily removed, after an upperhas been attached to the insole andbefore an outsol-e has been applied, bymelting at arelatively lowtemperature without damag t the insole.

These and other novel features and objects of the invention will beapparent from the accompanying drawings and hereinafter described andclaimed.

Referring to the drawings,

Fig. 1 illustrates an insole temporarily tacked upon a last;

Fig. 2 shows a shoe, comprising an upper and insole assembled on a last,with the lasting margin of the upper permanently secured to the Fig. 0shows a modified apparatus, partially brokenaway, for removing tacks inaccordance with another mode of operation;

Fig. '7 is a sectional view of the apparatus of Fig. 6, taken along theline VIIVH and viewed in the direction of the arrows, to furtherillustrate features of the invention; and

Fig. 8 illustrates still another modified apparatus for carrying out theinvention in accordance with a further mode of operation.

According to one aspect of the improvement in methods of making shoes,and as illustrated in the drawings, Figs. 1 through 5, an insole 20 isspotted and temporarily tacked in proper position upon a last 22 usingthe customary arrangement of tacks except that the tacks 24 employed areformed of a metallic alloy, such for example, as Rose or Woods Metal,characterized by a low melting point, a relatively high specific gravityand being capable of electrical conductivity. Then, after theusualopenations, such as upper assembling, pulling over, side, heel andtoe lasting, have been performed to attach the lasted up- ,per 26permanently to the insole, as by the staples 25, the temporary insole.fastening tacks 24 are removed by melting, the heat being generatedthroughout the tacks by high frequency electrical induction. 7

This operation may be accomplished by holding the shoe of Fig. 2 bottomdown upon the novel tack removing apparatus as shown in Figs. 3 and '4,where for the sake of brevity, only so much of the apparatus as includesmeans for melting the tacks in the forepa-rt of the shoe has beenillustrated; it is however to be understood that the tacks in the shankand heel portions may be simultaneously removed by similar melting meansassociated with the broken away portion of the apparatus andconcentrically located with the respective tacks.

through the table, the resilient layer and the base r plate. The edges29, 2c of this opening approximate the peripheral shape of a shoe bottombut are of a smaller dimension so that when a shoe is operativelypcsitioned above the opening the peripheral bottom margins of the shoewill extend over the edges 29 and be supported upon the upper surface ofthe table 28. Within this opening and slightly below the supportingsurface of the table are a series of electrical induction heating coils36 arranged in a predetermined pattern so that each coil may be inapproximate concentric alinement with one of the tacks 24. As an aid toproperly positioning the shoe to locate the tacks above the coils, thetable 28 is shown provided with a plurality of edge guides 35. The coilsmay be joined in an electrical series as illustrated, having theirterminal leads 32 and 3 connected to a suitable source of high-frequencyalternating current, not shown. Preferably, the conductor material forthese coilsis formed of a continuous tube so that a cooling medium, suchas Water, may be circulated throughout the coils to prevent them frombecoming so overheat-ed as to adversely affect the texture of shoeleather in close proximity thereto. 7

It will be seen that when the shoe is held bottom down upon the (worktable the insole tacks will be directly exposed to the heating coils.When thus subjected to the high-frequency magnetic fields surroundingthe coils the tacks are rapidly heated and become fluid in "a, veryshort time. Their melting speed, if desired, may be increased by theaddition of a small amount of copper or iron to the constituent alloy ofthe tacks.

In order to assure that no residue is left in the apertures 31; formedin the insole and last by the tacks, Fig. 4, the entire shoe may berapidly and vigorously vibrated during the melting out process. This maybe accomplished by imparting reciprocal up and down movement to the worktable 28 b the force of the rapidly rotating cam 40 striking against andelevating the under surface of the table, thereby upwardly distendingthe resilient layer 38. As the point of the cam moves downward thetable, drawn by the resiliency of the layer 38 and the force of gravity,descends to a level where it is once more engaged and elebe shakenfreely from out the holes 3'1, and to fall through the central openingsof the coils 3t and down through the cutout portion of the except thatthe method of removingthe plastic tacks and the apparatus therefor isessentially different.

In the case of plastic tacks, they likewise may all be removedsimultaneously by melting out, the heat being uniformly generatedthroughout the tacks by high frequency dielectric heating. After theshoe has been lasted as shown in Fig. 2, the subsequentmelting outoperation isperformed by holding the shoe down upon an apparatus similarto that of Fig. 3exceptthat the electrical induction heating coils arenot employed because the plastic tacks are non-conductors ofelectricity. Instead of the coils 36, the central cutout portion of thework table 23 may be provided either with a number of wav guide tubes ofconventional construction, as illustrated in Figs. 6 and 7, or with anarrangement Of electrodes as shown in Fig. 8. h

' Referring to the apparatus of Figs. 6 and '7, the wave guide tubes 44.should each be centrally positioned beneath one of the plastic tacks 46so 'as to direct its dielectric forces upwards into the tack. Theelectrical operating frequency for this apparatus will in each case bedependent upon the size, shape and composition of the tacks employed.The tubes 44 should be so selected as to obtain the minimum ofreflection back into the tube, and as to provide the most directionaland concentrated fields of dielectric forces into the tack. Thisdirectional concentration of the dielectricfields is an important factorfor two reasons; first, if the area of the insole encompassed by thefield isexcessive it may cause an arcing over to adjacent metallicobjects such as the staples 25, and secondly, since any leathercontaining moisture may have a relatively high factor of dielectricloss, this area may be deleteriously affected by overheating, thusweakening the structure of the shoe.

It will be noted that in the illustrated tube arrangement, the waves areguided from a suitable common generating source not shown, through abranch tube 48 leading into the several outlet tubes M and lta, thelatter tubes when extended being operatively positioned beneath thetacks in the shank and heel portion of the insole. These guide tubesbeneath each tack have a downward opening 45 so that the residue fromthe melted tacks may drop down and pass out through the bottom of thetubes.

When using th dielectric melting means shown in Fig. 8, the electrodes56 should be arranged in pairs beneath each tack and the faces of theelectrodes in each pair should be so positioned as to produce adielectric field which extends outward as far as the point of the tack.Here again it is important to restrict the area of insole leatherstrongly affected by the field because of the danger of scorching theleather and of arcing over onto metallic fastenings such as staples ortacks.

While the herein disclosed novel method of temporarily fastening a soleto the last has been exemplified in the drawings as employed in themanufacture of a cement type of shoe construction, it is to be clearlyunderstood that the invention and claims thereto are equally applicableto all types of shoe constructions wherein a sole is attached to a lastby fastenings which penetrate through the sole and into the last.

It is also to be understood that in the illustrations of the apparatusesfor removing the tacks the specific electrical arrangements are onlyshown by way of example. Since the choice of the best electrical heatingelements and their arrangement as to size, configuration, and positionmay vary according to the chemical, electrical and physicalcharacteristics of the particular fastenings employed, and since thischoice may be readily ascertained by one skilled in the arts ofinduction or dielectric heating, the scope of the present invention isnot intended to be limited to the specific arrangements disclosed in thedrawings.

The temperatures, which must necessarily be produced within thefastenings in order to efiect a complete melting thereof, will varyaccording to the material of which the particular fastening is composed.This invention contemplates the employment of such materials as willhave a relatively low melting point, so that complete fusion will takeplace below 400 F.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

1. That improvement in methods of making shoes which comprises the stepsof positioning an insole upon a last, temporarily securing said insoleto the last with readily fusible fastening means, and, after an upperhas been secured to the insole, removing the temporary fastening meansby subjecting them to heat sufficient to cause them to melt out from thelast and insole.

2. That improvement in methods of making shoes which comprises the stepsof positioning an insole upon a last, temporarily securing said insoleto the last by means of readily fusible fastenings, and, after an upperhas been secured to the iii 6 insole, removing said fastenings bysubjecting them to a high frequency field until the internal heat thusproduced throughout the fastenings causes them to melt out from the lastand insole.

3. That improvement in methods of making shoes which comprises the stepsof positioning an insole upon a last, temporarily securing said insoleto the last by means of readily fusible fastenings formed of anelectrically conductive alloy, and, after an upper has been secured tothe insole, removing fastenings by subjecting them to high frequencyelectro-magnetic fields until the internal heat thus produced throughoutthe fastenings causes them to melt out from the last and insole.

4. That improvement in methods of making shoes which comprises the stepsof positioning an insole upon a last, temporarily securing said insoleto the last by means of fastenings formed of a readily fusibleelectrically conductive alloy, and, after an upper has been secured tothe insole, removing said fastenings by subjecting them to highfrequency induction heating until the internal heat thus producedthroughout the fastenings causes them to melt out from the last andinsole.

5. That improvement in methods of making shoes which comprises the stepsof positioning an insole upon a last, temporarily securing said insoleto the last by means of fastenings formed of readily fusible dielectricplastic material, and, after an upper has been secured to the insole,removing said fastenings by subjecting them to high frequency electricfields until the internal heat thus produced throughout the fasteningscauses them to melt out from the last and insole.

6. That improvement in methods of making shoes which comprises the stepsof positioning an insole upon a last, temporarily securing said insoleto the last by means of fastenings formed of a readily fusible materialhaving a high dielectric loss, and, after an upper has been secured tothe insole, removing said fastenings by subjecting them to highfrequency dielectric heating until the internal heat thus producedthroughout the fastenings causes them to melt out from the last andinsole.

7. A step product for use in the manufacture of shoes comprising a lastand a sole member secured to the bottom of the last by readily fusiblefastenings.

8. A step product for use in the manufacture of shoes comprising a lastand a sole member secured to the bottom of the last by readily fusiblemetallic fastenings.

9. A step product for use in the manufacture of shoes comprising a lastand a sole member secured to the bottom of the last by readily fusibleplastic fastenings.

10. A step product for use in the manufacture of shoes comprising a lastand sole member secured thereto by fastening means which may thereafterbe melted out by fusion at a temperature below 400 F.

JOHN J. BROPHY.

REFEREI IGES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,790,19'1 Winkley Jan. 27, 19311,825,206 Rivas Sept. 29, 1931 2,383,992 Sherman Sept. 4, 1945 2.415.025Grell et a1. Jan. 28, 1947

